The present invention relates to an inspection data processing technique which makes it possible to judge a defect as to whether it is fatal or not, the defect which is generated on a semiconductor wafer, a mask, a circuit pattern of liquid crystals, or the like, and in particular it relates to a technique suitable for judging the fatality of a defect detected by a visual inspection apparatus or the like in the manufacturing process of a semiconductor device or for the selection of defects on the subject of review or analysis, and a technique suitable for the investigation of a cause generating a fatal defect and for the planning of the countermeasure for it.
In a manufacturing line of semiconductors, it is essential for the upkeep and the upgrade of the yield rate to feedback the cause of generating a defect to the manufacturing process and to the manufacturing apparatus to remove the defect, and it is essential to plan a measure by finding out the cause of the defect as early as possible. In order to achieve the above object, it is important to find the defect by a visual inspection apparatus and to perform the data analysis in an early stage.
A Japanese Patent Laid-open No. Hei 10-107102 is known as a conventional defect analysis system to be used for the investigation of the cause of a defect in an early stage. The conventional defect analysis system is composed of: a visual inspection apparatus for detecting the defect on a wafer, an analysis station which extracts a group of defects being in a crowded state out of the detected defects, and further extracts one arbitrary defect or two or more arbitrary defects out of the extracted group of defects as a representative defect or defects, and a review station which observes only a representative defect or representative defects extracted in the analysis station for judging the category of the defect and gives identical category to the above-mentioned category also to the other defects which compose the defect group than the representative ones.
The visual inspection apparatus transmits information on the position data or the size data of a defect on a semiconductor wafer, for example, a defect on a circuit pattern such as a short circuit or a breaking of a wire which occurs on a wafer process, or a defect caused by the sticking of a foreign material, to the analysis system which stores these data. Next, the inspected wafer is transferred to the review station, and a stage is moved to the position of the coordinates data of a detected defect to classify the category of the defect with an enlarged image of it.
It is described that, in a visual inspection apparatus, a threshold value which judges whether a defect exists or not from a difference image between a detected image and a reference image is changed with the change in the distribution of brightness in the background in xe2x80x9cAn Advanced Yield Learning System for 64 M DRAM Production and Beyondxe2x80x9d in Technical Proceedings SEMICON/Japan, 1996, pp. 2-19 to 24, which is a prior art.
However, in the prior art mentioned in the above, it is not described to classify defects into fatal/not fatal ones based on the inspection data of the defects detected with the visual inspection apparatus in the review and the analysis work. The fatal defect means, in this case, that the defect has a high probability of causing an electrical trouble in a circuit pattern.
The review work has to be performed by hands, so that it takes much time to do the work; therefore, it may disturb the improvement in the throughput in the inspection process. The judgment of the fatality of a defect has been entrusted to a specific technical expert having not only an ability of observing the defect itself but also the knowledge concerning the function or structure of the circuit pattern in the range in which the defect exists. Further, there has been a problem that the judgment result can be different by persons because the judgment standard are different by persons even among the experts.
In order to solve the above-mentioned problems, a first object of the present invention is to provide a method and an apparatus for processing an inspection data in which a fatal defect can be accurately selected based on inspection data detected with a visual inspection apparatus.
A second object of the present invention is to provide a method and an apparatus for processing an inspection data which makes it possible to improve the throughput in a review work or an analysis work by an arrangement for making a fatal defect be accurately selected in a review/analysis apparatus with precision to be able to narrow down subjects into one or ones which are really in need of the review work or the analysis work.
A third object of the present invention is to provide a method and an apparatus for processing an inspection data in which the selection of subjects of review/analysis can be performed automatically.
A fourth object of the present invention is to provide a method and an apparatus in which the inspection data can be edited, retrieved, displayed and output to the external utilizing the information of the results of the inspection and the analysis, and to provide a method and an apparatus for effectively performing an analysis for observation of a cross section of a defect.
In order to achieve the above-mentioned objects, in the present invention, the judgment of fatality is performed according to the category of a defect and to the kind of an area in which a defect exists on an inspection subject based on inspection data (coordinates of the defect and characteristic data of the defect) about the defect generated on the inspection subject detected with a visual inspection apparatus.
In other words, the judgment of the fatality of a defect is performed with first fatality judgment data which judges the fatality according to the kind of the area on an inspection subject, and with second fatality judgment data which judges the fatality according to the category of the defect. These data are prepared being stored beforehand.
In the present invention, a manufacturing line is managed based on the number of fatal defects judged with the second fatal judgment data.
In the present invention, a first fatality judgment is performed according to the kind of an area in which a defect exists on an inspection subject based on inspection data (coordinates of the defect and characteristic data about the defect) of a defect generated on an inspection subject and detected with a visual inspection apparatus. A defect to be given a category is selected based on the first fatality judgment.
In the present invention, a first fatality level is calculated according to the kind of an area in which a defect exists on an inspection subject based on inspection data (coordinates of the defect, and characteristic data concerning the defect) concerning the defect generated on the inspection subject which is detected with a visual inspection apparatus. According to the calculated level of the first fatality, a defect to be given a category is selected. For the selected defect, the category is given utilizing a review apparatus, and for the calculated first fatality level concerning the defect, weighting (second fatality judgment data) is performed corresponding to the given category to calculate a second fatality level.
In the present invention, a defect to be analyzed in an analysis apparatus is selected according to the second fatality level.
In the present invention, the number of defects is calculated for categories according to the area of the defect for every different kinds of areas on an inspection subject based on inspection data (coordinates of the defect, and characteristic data concerning the defect) concerning the defect generated on the inspection subject detected with a visual inspection apparatus, and the result is output to an external circuit.